Details of GM's self-driving system have been revealed — but the feds aren't impressed

General Motors' semi-autonomous "Super Cruise" system will allow drivers to
take their hands off the steering wheel for extended periods, but
will stop the vehicle automatically if drivers are not attentive,
according to a government letter made public on Monday.

GM, the largest US automaker, unveiled the planned technology
that will allow its vehicles to take over driving on
highways in September 2014.

But if the road has too many twists and turns or the vehicle
detects the driver is not paying attention, it issues a series of
alerts. If the human driver does not take over, the vehicle will
automatically slow down and then put on the hazard lights.

GM, which initially planned to unveil the technology on the CT6
in late 2016, said in January it would not unveil Super Cruise
until 2017.

The National Highway Traffic Safety Administration (NHTSA) said
in a letter to GM that it was permissible for the automaker to
automatically activate hazard lights if a driver fails to respond
to alerts by a self-driving vehicle that has brought itself to a
stop, but it raised concerns over whether the system is
safe.

In March, GM asked NHTSA to confirm it was appropriate for the
vehicle to activate the hazard lights if it was brought to a
stop. NHTSA said in its letter it urged GM to "ensure that this
fallback solution does not pose an unreasonable risk to safety."

NHTSA said GM's Super Cruise system will in some situations
"alert the driver to resume steering." It said that if the driver
is incapacitated, unresponsive or otherwise unwilling to retake
the controls, "Super Cruise may determine that the safest thing
to do is bring the vehicle slowly to a stop... in or near the
roadway."

GM's monitoring system has facial recognition software that can
detect if a driver is falling asleep or not paying attention,
spokesman Kevin Kelly said Monday. If so, the system issues
alerts: a red visual display telling a driver to take control
followed by a seat vibration and then a recorded audio message.
If drivers ignore all those, GM's OnStar system will communicate
with the driver.

GM confirmed details of the Super Cruise system outlined by NHTSA
in a separate letter reviewed by Reuters.

Concerns about vehicles that drive themselves for limited periods
were raised after the May 7 death of Ohio technology company
owner Joshua Brown in a Tesla Model S while the car's
semi-automated Autopilot system was engaged. NHTSA is still
investigating that crash.

In September, Tesla updated its semi-autonomous driving system
Autopilot with new limits on hands-off driving and other
improvements that likely would have prevented a fatality in
May, the company said. The updated system will require drivers to
respond to audible warnings to take back control of the car.

Similar systems due on the market in coming years include Traffic
Jam Pilot from Volkswagen's Audi unit in 2018.